Composition for producing protective coatings



Patented Aug. 26, 1952 COMPOSITION FOR. PRODUCING PROTECTIVE COATINGS- Bertha S. Tuttle, Newton, and George E. Jacobs;

Boston, Mass., assignors to J. N. Tuttlc; Inc.-, Newton, Mass, a corporation of Massachusetts.

N Drawing. Application April, 1, 1950,

Serial No. 153,494

This invention relates toaprotectlve. coatings of the type disclosed in U. S. Patent No. 2,295,063,

granted September 8, 1942.

In producing protective coatings of t e type disclosed in the above patent it is necessary to observe carefully thevarious factors which are responsible for imparting a satisfactory coating. So long as the operation isconducted under the supervision of. a chemistor one skilled in the art, little if any difliculty is usually encountered, but in many establishments the process is in charge of an unskilled person who does not recognize the development of adverse conditions and unsatisfactory and defective work invariably results.

The principal object of the present invention is to provide a composition which may readily be dissolved in a prescribed amount of water to produce a stable treating solution having the correct pH, solids content, etc., and which does not undergo deterioration or change after a reasonably long period of use, thereby to enable an unskilled operator to practice successfully the above-identified process merely by ob serving temperature and time of treatment.

Further objects will be apparent from a consideration of the following disclosure which embodies several examples illustrative of our improved composition.

In accordance with the present, invention a metallic article having a protective coating consisting essentially of an insoluble porous crystalline surface in the form of an insoluble metal salt of the group consisting of phosphates and oxalates is first subjected to an aqueous solution of sodium aluminate and di-sodium phosphate for a period of from less than five minutes to fifteen minutes or more, depending upon the temperature. The phosphate or oxalate coating may be produced in accordance with the procedures known in the trade as Parkerizing and Bonderizing, which produce phosphate coatings, and the Loxal process which produces an oxalate coating.

The preferred composition consists essentially of sodium aluminate and disodium phosphate, although minor amounts of the monosodium salt may be used along with a major portion of the disodium salt as hereinafter illustrated. Sodium borate is also usable as an equivalent of disodium phosphate. The ratio of the weight of sodium aluminate to that of the phosphate may vary from about 1:1 to 1:3, but the preferred proportions are of the order of 2:3 of the weight 4 Claims. (01. 1486.1)

of "the sodium aluminate-sodium phosphate mixture; If desired, zinc phosphate may be incorporated in an amount varying from lessthan 1% toabout 10%.

After having subjected the phosphate or oxalate" coated article to the treating solution for a period sufficient to causethe composition to react, as described more fully in'the above-mentioned patent, the article maythen be rinsed in water, dyed in a hot aqueous bath, then rinsed, dried and oiled in conventional manner.

Illustrative compositions are as follows:

Example 1 Parts (by weight) sodium aluminate 5 Disodium phosphate (anhydrous) 6 Monosodium phosphate (anhydrous) 1 Example 2 Parts (by weight) Sodium aluminate I I 5 Disodium phosphate (anhydrous) 8 Example 3 Parts (by wei ht) Sodium aluminate 5 Disodium phosphate (anhydrous) 8 Zinc phosphate -I. 0.24

The recommended procedure in using any of the above compositions is to dissolve them in about 88 parts of warm water, thereby to provide a treating bath or solution which in use is maintained at a temperature between and F. The phosphateor oxalate-coated article is dipped in the bath for a period of about five to eight minutes, and then rinsed in water, thereby producing a coating which'can be permanently dyed with a wide range of commercially available dyes.

A fast black color is generally difficult to produce, but a chemically coated article treated as above described may readily be colored black by the following treatment:

The article after being rinsed with water is dipped into an aqueous dye bath maintained at or about the boiling point and consisting essentially of 2% Hematin and 1% Fustic. The time of treatment is between five and ten minutes, after which the dyed article is removed, rinsed, dried, and either waxed or oiled. In any case a fast color is not only produced, but also greatly improved rust-resisting properties are imparted.

The treating composition is quite stable and may be put up in packages or containers which may be kept indefinitely. The composition produces a stable bath having the correct pI-I when dissolved in the prescribed quantity of water. Hence by merely emptying a packaged amount of the composition in the prescribed amount of water an unskilled operator may make up a reliable treating solution which does not undergo appreciable deterioration for relatively long periods of time. Hence, the usual supervision of a skilled worker may be eliminated.

The present disclosure is'for the purpose of illustration and various modifications of the foregoing may be made without departing from aluminate and about 8 parts by weight of dithe spirit and scope of the invention, as set forth in the appended claims.

We claim:

1. A composition for use in treating chemical 1y coated articles consisting essentially of a mixture of sodium aluminate and disodium phosphate in proportions between 1:3 and 1:1, by weight.

2. A composition for use in treating chemically coated articles, consisting essentially of approximately 5 parts by weight of sodium aluminate, approximately 1 part by weight of monosodium phosphate, and 6 parts by weight of disodium phosphate. v

3. A composition for use in treating chemsodium phosphate.

BERTHA S. TUT'ILE. GEORGE E. JACOBS.

REFERENCES CITED I The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,722,137 Frischer ,July 23, 1929 2,102,219 Raymond Dec. 14, 1937 2,395,126 King Feb. 19, 1946 2,431,946 Lurie Dec. 2, 1947 2,478,954 Tuttle et a1 Aug. 16, 1949 FOREIGN PATENTS Number Country Date 390,249 Great Britain Apr. 6, 1933 390,435 Great Britain Apr. 6, 1933 292,667 Italy Jan. 27, 1932 

1. A COPMPOSITION FOR USE IN TREATING CHEMICALLY COATED ARTICLES CONSISTING ESSENTIALLY OF A MIXTURE OF SODIUM ALUMINATE AND DISODIUM PHOSPHATE IN PROPORTIONS BETWEEN 1: 3 AND 1:1 BY WEIGHT. 